This invention relates to a device for providing a dose of a liquid or solid to a larger container. More particularly, this invention relates to a dispensing device for providing a dose of substances, such as active agents, to a wash tub.
The treatment of fibers, fabrics and laundry with substances, such as cleaning and bleaching agents, to improve the cleanliness and appearance of such treated materials is a well known operation. It has become customary to introduce a quantity of substances into the wash water in the usual washing of fabrics in an automatic washing machine. In some instances predetermined amounts of the substances are packaged in water soluble packets that are thrown into the wash water with the fabrics, and in some instances the machine operator pours the substances directly into the wash water from a container according to directions. In both these instances the substances may remain concentrated in one region of the wash water, and to overcome this problem it has become known to place the substances in a doser device within the wash water to gradually dispense the substances into the agitated wash water currents as fabrics are being washed.
Doser devices are of various shapes and have various sized openings for the dispensing of the substances. Some doser devices have perforated casings which are designed to contain the substances until the first few turns of the drum. U.S. Pat. No. 4,014,105 discloses the use of a doser device containing a conditioning liquid, such as fabric softener and/or anti-static agents, which is put into an automatic dryer and is tumbled with laundry being conditioned in the automatic dryer. The doser discharges the solution of conditioning agent through perforations in the container, so that the agent is applied to the laundry and conditions it. Similarly, U.S. Pat. No. 4,703,872 No. (a counterpart of French Patent No. 2,570,720 and EP 0152,359B2), U.S. Pat. No. 4,874,107 (a counterpart of EP 028B,345B1) and U.S. Pat. No. 3,400,808 provide various sized openings in the doser device to distribute the contents of the device, usually a liquid detergent, during a washing cycle. These doser devices are mainly directed for use with liquid detergents and have comparatively large dispensing openings. The contained liquid detergent is released very rapidly.
The evolution of detergent formulae is towards an increasing concentration of the substances. Further, there is an increased use of solid bleaches. The use of such detergents and solid bleaches leads to the danger of staining or discoloring fabrics and particularly when such fabrics come into contact with undissolved solid particles of these substances. The substances from the doser device should not contact any fabrics until fully dissolved. The substances preferably should remain in the doser until dissolved. The existing dispensing devices do not prevent the possibility of fabrics coming into contact with the substances in a highly concentrated condition and which thus possibly stain or discolor the fabric. The problem of the prior art that the present invention overcomes is the potential for staining and/or discoloration if a solution or agent, such as a bleaching agent or concentrated laundry detergent, comes into contact with the fabric before any significant dilution by the wash water. The staining and/or discoloration is due to the expulsion of the agent onto the fabric when it is in a high concentration.
The present invention overcomes these problems through the exchange of the substances in the doser device and liquid from the wash tub. This is accomplished by the structure of the doser device which provides for an increase and decrease in the volume of the doser during its use in a wash tub. In a preferred embodiment, the structure to increase and decrease the volume of the dispenser is a bellows arrangement in one or more surfaces of the closer. The turning of the drum of a washing machine causes the substances in the doser device to enter the wash water as liquids. The substances in a decreased concentration then contact the fabrics to be washed. The doser devices of the present invention are durable but flexible, and have small apertures so as to contain a powder or concentrated liquid active inside the doser device and only allow the passage of dissolved solid substances and lower concentration liquids into the wash tub, thereby preventing the chance of staining and/or discoloration of the fabric in the laundry.